Cells and organisms must coordinate their metabolic activity with changes in their nutrient environment. This coordination is achieved via the signaling networks that integrate local and systemic nutrient inputs and relay nutrient status to the control of cellular anabolic and catabolic processes. This task canbe carriedoutby the RAS-RAF-MEK-ERK cascade, a signaling system that is commonly activated by various growth factors and oncogenicevents.Inresponsetoamitogenfactorsuchastheepithelialgrowthfactor(EGF),ERKisactivated and promotes cell proliferation and differentiation by regulating activity of transcription factors involved in cell cycleprogressionandproliferation.However,muchlessisunderstoodabouthowERKsignalingdirectlycontrols metabolicprocesses.TargetingthekinasesRAF,MEKorERKiscurrentlyastrategyemployedtotreatseveral diseasesincludingcancer,type2diabetes,metabolicdisordersandneurodegeneration,howevermechanisms of resistance often occur. Therefore, elucidating the downstream targets of ERK and more specifically the molecular mechanisms by which ERK signaling drives metabolism is of great interest in order to identify new therapeutic strategies against ERK driven disease. Recently we discovered that the mechanistic target of rapamycin complex 1 (mTORC1) stimulates synthesis of purines and pyrimidines de novo through different molecularmechanisms.Nucleotidesplayacentralroleinmetabolismatafundamentalandcellularlevel.Purine andpyrimidinebasescanbesynthesizeddenovoorrecycledthroughthesalvagepathways.Nucleotidescarry packets of chemical energy (e.g. ATP, GTP) throughout the cell to the many cellular functions that demand energy,whichinclude:synthesizingnucleicacids,proteinsandcellmembranes.Underthisproposal,wepropose tostudytheinfluenceofERKsignalingonnucleotidesynthesis.WehaveidentifiedthatERKsignalingstimulates de novo purine synthesis in various settings through posttranslational modification of the enzyme PFAS (phosphoformylglycinamidinesynthase)whichbelongstothedenovopurinesynthesispathway.Weproposeto dissect the molecular mechanisms underlying this regulation (Specific Aim1). We will determine the role of the ERK-PFASaxisinthecontrolofcellgrowth(SpecificAim2).Furthermore,wewilldeterminetheimplicationof thisregulationinERK-mediatedbiologyanddisease(SpecificAim3).Thus,theoverallgoalofthisproposalisto decipher the molecular mechanisms by which ERK controls de novo nucleotide synthesis in normal and pathological settings. We anticipate that the proposed studies will yield new insights into how nucleotide synthesisisregulatedbyERKandwilluncovertherapeutictargetstoperturbERK-mediateddisease.

Public Health Relevance

GiventheinvolvementofERKsignalinginseveraldiseasesincludingAlzheimerdisease,diabetes,obesityand cancer, this proposal will establish a new level of understanding of how ERK directly regulates activity of the metabolic pathways essential for cellular homeostasis. Our preliminary data place us in the unique position to uncoverandunderstandatabiochemicalandmolecularlevelnewregulatoryprocesses,newbiomarkersand newpotentialstrategiesthatareneededforpersonalizedtherapeuticinterventioninmetabolicdiseasesthatcan bedrivenbyimproperERKsignaling.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM135587-02
Application #
10078280
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Xu, Jianhua
Project Start
2020-01-01
Project End
2024-12-31
Budget Start
2021-01-01
Budget End
2021-12-31
Support Year
2
Fiscal Year
2021
Total Cost
Indirect Cost
Name
Northwestern University at Chicago
Department
Biochemistry
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611